/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package cn.icanci.learn.v1.aop3;

import java.lang.reflect.InvocationTargetException;

/**
 * @author icanci
 * @date Created in 2021/06/27 22:03
 * @version 1.0
 */
public abstract class AbstractHandler {
    /**
     * 下一个处理单元
     */
    private AbstractHandler next;

    public void setNext(AbstractHandler next) {
        this.next = next;
    }

    /**
     * @param targetMethod TargetMethod
     */
    abstract Object invoke(TargetMethod targetMethod) throws InvocationTargetException, IllegalAccessException;

    /**
     * proceed
     * @param targetMethod targetMethod
     * @return targetMethod
     */
    public Object proceed(TargetMethod targetMethod) throws InvocationTargetException, IllegalAccessException {
        if (!hasNext()) {
            return targetMethod.getMethod().invoke(targetMethod.getTarget(), targetMethod.getArgs());
        }
        return next.invoke(targetMethod);
    }

    /**
     * 是否有下个节点
     * @return
     */
    public boolean hasNext() {
        return next != null;
    }

    public static class HeadHandler extends AbstractHandler {

        /**
         * invoke
         * @param targetMethod TargetMethod
         */
        @Override
        Object invoke(TargetMethod targetMethod) {
            return null;
        }
    }
}
